Recounting one of the city’s worst police brutality scandals, Abner Louima again testified yesterday that Charles Schwarz held him down during the 1997 sodomy attack – but his credibility came under fire when he admitted he previously committed perjury.

During a grueling two-hour cross-examination at Schwarz’s retrial yesterday, Louima admitted telling a sensational lie to the grand jury – quoting an attacker as saying, “This is Giuliani time. It’s not Dinkins time.”

Defense attorney Ronald Fischetti had asked him point-blank if he committed perjury and Louima paused and then matter-of-factly answered, “Yes.”

Louima was the first witness in trial. Although he has never visually identified Schwarz as his second assailant, he said he’s sure it was the driver of the car that brought him to the 70th Precinct station house.

The cop who led him to the bathroom was the same cop who drove him to the station house – a duty that Schwarz admitted he performed that night.

“The driver put his foot hard on my mouth and said, ‘Shut up,’ ” Louima said, recounting how his screams were stifled as convicted attacker Justin Volpe kicked him in the groin.

It was the seventh time Louima has testified under oath – and his accounts have admittedly shifted over time. Assistant U.S. Attorney Lauren Resnick chalked up Louima’s misstatements to the trauma he endured.

He also admitted that he initially told investigators that no one restrained him during the attack, and that it was “the driver” who wielded the stick and sodomized him.

“Abner Louima is not on trial here,” Resnick said.

But Fischetti countered, “Being the victim in such a horrific crime does not give him the right to take the witness stand and lie.”

Fischetti focused on the view that Schwarz was misidentified.

“There was a second police officer in the bathroom, but the second officer was not Charles Schwarz,” Fischetti said, adding that it was Thomas Wiese, Schwarz’s former partner, who has admitted he led Louima to the bathroom.

When the lawyer asked Louima if Schwarz and Wiese “looked alike so that you could not tell them apart by face,” Louima replied, “Yes” – but added that Schwarz was “more muscular” in his upper body.”

Schwarz is charged with violating Louima’s civil rights by participating in the attack, and then lying on the witness stand at a previous trial when he denied being anywhere near the bathroom.

He had already served nearly three years in prison when an appeals court reversed his previous convictions.

THE SCHWARZ TRIAL

HIGHLIGHTS: Abner Louima admits on the stand he perjured himself when he told a grand jury that cops said it was “Giuliani time” during his assault. He also said he’s never been able to physically identify Charles Schwarz as the man who led him to the bathroom.

QUOTE OF THE DAY: “Officer Volpe kicked me in my groin. I yelled. The driver ( the cop car, who prosecutors have identified as Schwarz) put his foot on my mouth and told me to shut up…. The driver brought me up on my feet and Officer Volpe put something in my rectum.” Louima testified.

ON TAP TODAY: NYPD Sgt. Jeffrey Fallon, the desk sergeant during the attack, will testify for the prosecution. Sgt. Eric Turetzky and Mark Scoffield will also take the stand. They both testified in Schwarz’s first trial that they saw him lead Louima to the bathroom.